Anti-pitch suspension

ABSTRACT

A vehicle suspension is designed to utilize lateral movement of the body of the vehicle relative to the wheels in order to control the sway or roll of the vehicle body relative to the ground. Several systems are disclosed for translating the roll tendency of the body into lateral movement of the body relative to the wheels without body roll. This system may be also used to control other suspension parameters such as ride height, spring rates, caster, camber, and toe-in. The system is also effective in reducing the load sensitivity of the suspension to understeer or oversteer. The principle of the invention may also be used to control dive during braking or squat during acceleration.

RELATED APPLICATIONS

This application is a continuation-in-part of my application, Ser. No.361,534, filed Mar. 23, 1982 now U.S. Pat. No. 4,484,767.

BACKGROUND OF THE INVENTION

Over the years, the roll of a vehicle such as an automobile about itslongitudinal axis has always been considered a problem to a greater orlesser extent. Particularly on more softly suspended vehicles, this rollcan become quite disconcerting to a passenger and adversely effecthandling. A number of attempts have been made at reducing or eliminatingroll, the most common and preferable of which is the use of antiroll orantisway bars. Such bars have a tendency to reduce the amount of sway,and while such bars typically have no effect on bumps affecting bothwheels of an axle, the stiffer the sway bar gets, the more ride qualityis compromised on one wheel to a suspension movement or deflection atthe other wheel. The use of a complicated frame and system to allow acar body to bank into the turn about an axis above the body center ofgravity has also been attempted as typified in U.S. Pat. No. 2,234,676.Any number of other systems have been produced which prevent roll of thevehicle body relative to the wheels such as U.S. Pat. No. 2,770,468.None of the systems known, however, have utilized lateral translationalmovement of the body relative to the wheels to resist roll. Any lateralcompliances which may exist in presently known systems are placed thereonly for the purpose of ride comfort in absorbing shocks and vibrationstransmitted through the wheels. The use of compliance for that reason isdemonstrated in U.S. Pat. No. 2,309,811. None of the known systemsutilizes lateral translational movement of the body center of gravity toreduce roll.

SUMMARY OF THE INVENTION

It is the object of this invention to produce a suspension system whichis capable of eliminating or reducing body roll. If desired, the systemmay even be utilized to allow banking of the vehicle body toward theinside of a turn. As used hereinafter the terms inner and outer refer tothe direction in which the vehicle is turning and the oppositedirection, respectively. These results may be accomplished by providingmeans for the lateral forces on the vehicle during cornering to producelateral translational movement of the vehicle body relative to thewheels and wheel supporting means, and utilizing such movement tocontrol body roll. The supporting means may either be a beam axle in thecase of a solid axle car or may be a-arms, MacPherson strut or any otherconventional suspension pieces which may be used to yield an independentsuspension. A semi-independent suspension may also be obtained with atrailing twist axle as found on GM's X and J bodies, Chrysler's L and Kcars, and Volkswagon Rabbit. While the normal tendency of the vehicleduring roll is to increase the compression of the outer spring and toreduce compression or even extend the inner spring, the instantinvention is intended to create an additional means of providing thatcompression and extension by utilizing the lateral translationalmovement of the vehicle. The springs (including but not limited to leaf,coil, gas or rubber) may be mounted at any angle relative to the lateralmovement of the wheel supporting means so that lateral movementincreases compression of the outer spring and reduces compression orextends the inner spring directly. Alternatively, springs of varioustypes including antisway bars may be mounted via a linkage which may bemechanical or hydraulic. This linkage operates as a jacking system whicheffectively converts the lateral translational movement of the bodyrelative to the wheel locating means into a mechanical compression andextension of the springs either by way of hydraulic cylinders or by wayof a mechanical jacking system. The jacking is an increased compressionof the outside spring and decreased compression of the inside spring.The mechanical jacking system which is utilized may be formed with solidlink pieces or may utilize a cable arrangement. Such linkage may be nomore than a simple diagonal link piece.

The principal of the instant invention may also be utilized to provide asuspension system with anti-dive and anti-squat capabilities. Towardsthis end, movement of the wheel is allowed in a fore-aft plane and thespringing medium is mounted at an angle from front to rear and allowedto pivot such that upon braking, the spring's lower end moves rearwardlythereby increasing compression of the spring while at the same timeeffectively lengthening the vertical length of the spring.

These and other objects and advantages of my invention will appear morefully from the following description made in conjunction with theaccompanying drawings wherein like reference characters refer to thesame or similar parts throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal plan view of the instant invention;

FIG. 2 is a longitudinal plan view of an alternate embodiment;

FIG. 3 is a longitudinal plan view of another alternate embodiment;

FIG. 4 is a longitudinal plan view of yet another alternate embodiment;

FIG. 5 is a longitudinal plan view of still another alternateembodiment;

FIG. 6 is a longitudinal plan view of an alternate embodiment;

FIG. 7 shows a multiple axle-jacking system; and

FIG. 8 is a side plan view showing an embodiment having anti-divecapabilities.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 discloses an antiroll suspension 10 which is generally used forsuspending a vehicle having wheels 12 from a body 14. It is understoodof course that the term body 14 is used in a general nature and mayinclude situations where the frame is integral with the body or whereina separate frame per se is present. A wheel supporting means 16 is inthe case of the embodiment of FIG. 1 comprised essentially of a beam orrigid axle 18. Wheel supporting means 16 is used to rotatably mountwheels 12 thereon. As will be seen more fully hereinafter, wheelsupporting means 16 may also allow for an independent suspension and maygenerally be characterized as the portion of the suspension which inconjunction with wheels 12 moves laterally relative to body 14. Body 14is suspended from wheel supporting means 16 by suspending means 20.Suspending means 20 are comprised of inner and outer spring means 22 and24, respectively. Spring means 22 and 24 may be coil, gas, or otherconventional springing media. As shown in the drawing figures, thevehicle, when in the cornering position shown in phantom, is corneringin the direction of the right side of each figure with the right springmeans 22 being designated the inner spring means and the spring on theleft being designated the outer spring means 24. Of course if thevehicle were to corner in the opposite direction this notation would bereversed. Spring means 22 and 24 each have first ends 22a and 24aattached pivotably to attachment points 26 on axle 18 adjacent wheels12. Spring means 22 and 24 also have second ends 22b and 24b pivotablyattached to chassis pickups 28 to body 14. As can be seen in FIG. 1,spring means 22 and 24 angle upwardly and toward each other fromattachment points 26. In this embodiment, it is essentially the mountingangle of spring means 22 and 24 which act as the means for translatingthe lateral inertia of the vehicle and particularly vehicle body 14 intolateral movement of body 14 relative to wheel supporting means 16 andwhich converts such movement into increased compression of outer springmeans 24 and decreased compression of inner spring means 22 compared toa more conventional suspension system. This movement may be seen in thephantom in FIG. 1 and shows the jacking effect. As can be seen,depending upon the spring rates, angle of mounting, and the like, swaymay be absolutely controlled to whatever degree desired and othersuspension parameters such as ride height may also be controlled. Alsopart of suspending means 20 may be optionally a lateral shock absorber32. In general lateral shock absorber 32 may be tuned so as to preventhigh frequency lateral movement of supporting means 16 relative to body14 during bumps and other such high frequency movements while at thesame time allowing lateral movement during cornering which is consideredrelatively low in frequency. In the particular configuration shown inFIG. 1, lateral shock absorber 32 has first and second ends 32a and 32b,respectively. First end 32a attached to axle 18 at attachment point 34while second end 32b is attached to body 14 at attachment point 36. Asshown in FIG. 1, attachment point 34 is located below attachment points26. This set up gives the effect of providing different roll centersduring cornering and during high frequency movements such as bumps, alower roll center being desirable in the bump mode than in the corneringmode. It is to be stressed that the lateral movement taking placebetween body 14 and supporting means 16 is primarily translational innature and is not to be confused with banking or sway present in priorsuspension systems. It is in fact desired in most conventional systemsthat lateral movement not take place.

Turning to the embodiment shown in FIG. 2, the FIG. 2 embodimentutilizes a leaf spring 121. Inner and outer portions 122 and 124 of leafspring 121 act in much the same way as the spring means 22 and 24 do inthe FIG. 1 embodiment. Where possible, parallel numbers have been usedto describe the various embodiments. In this embodiment link 140 acts asa simple form of linkage jacking system. Such a link may also be usedwith other types of springs such as antisway bars. Wheels 112 aremounted to wheel supporting means 116 which is comprised of an axle 118.Supporting means 116 is mounted to body 114 by suspending means 120which is comprised of a lateral shock absorber 132 and translating means130. Translating means 130 is in turn comprised of leaf spring 121 andlinks 140. Leaf spring 121 has a region of increased flexibility 123intermediate chassis pickups 122b and 124b. Spring 121 has first andsecond sides 122 and 124 which are the inner and outer spring means,respectively. Inner spring end 122a has mounted thereto second end 140bof one of links 140. The other end 140a of the link 140 is attached toaxle 118 and at attachment point 126. The other link 140 is attached atits upper end 140b to leaf spring 121 second end 124a. The other end of140a of the other link 140 is attached to the other attachment point 126on axle 118. Similarly, lateral shock absorber 132 has a first end 132aattached to axle 118 at point 134 and second end 132b attached to body114 at point 136. In the embodiment shown in FIG. 2 attachment point 134is approximately even with attachment point 126 thereby yielding noappreciable change in roll center during bump and cornering modes.

Turning to the embodiment shown in FIG. 3, it can be seen that this is avariation of the embodiment shown in FIG. 1 adapted so as to allowindependent suspending of wheels 312. In particular now wheel supportingmeans 316 is now comprised of a subframe 350 which is attached to body314 by means of linkage 352. Linkage 352 is shown in schematic form onlyand any suitable linkage which allows the lateral motion of subframe 350relative to body 314 is suitable. Linkage 352 may be arranged so as toallow some rotation of the subframe to control chamber. Attached in turnto subframe 350 are independent mounting means 354 to which are attachedwheels 312. As see in FIG. 3, independent mounting means 354 is a doubleA-arm type of suspension. Of course other conventional independent andsemi-independent suspension systems may be utilized to achieve the sameresult and the use of other such conventional mechanisms is within thecontemplation of all embodiments solid axles being shown in the laterfigure only for simiplicity. Suspension means 320 again comprises innerand outer spring means 322 and 324 which are mounted to independentmounting means 354 at the bottom end thereof in a fashion to that shownin FIG. 1 and which allows independent movement of wheels 312 in thebump mode while retaining the lateral movement of the instant inventionand which is shown more fully in FIG. 1. FIG. 3 also shows antisway bar392 and links 394 such that cornering causes antisway bar 392 and links394 to act in a manner similar to leaf spring 121 and links 140 in FIG.2.

Turning to the embodiment shown in FIG. 4, rocker arms 470 and 472 areused to provide a jacking effect on inner and outer springs 422 and 424,respectively. In particular, upper end 422b of inner spring means 422 ismounted to attachment point 470c of inner rocker arm 470, the outer endof rocker arm 470 is attached at 470a to link 474 while the inner end470b of rocker arm 470 is attached to body 14. Similarly, outer rocker472 is attached at inner end 472a to link 476 and at outer end 472b tobody 14. The upper end 424b of spring means 424 is attached to rocker472 at 472c. The lower ends 422a and 424a of springs 422 and 424 areattached to axle 418 at attachment points 426. A bell crank 460 ispivotally mounted to body 414 at chassis pickup 428. Ends 462 and 464 ofbell crank 460 are attached to links 474 and 476, respectively.Similarly, link 478 connects bell crank bottom 466 at attachment point426 on axle 418. As can be seen in FIG. 4 in phantom, the lateral motionof body 414 causes the movement of bell crank 460 providing a jackingeffect which increases the compression of outer spring 424 and decreasesthe compression of inner spring 422. It is to be noted that while FIG. 4shows the use of solid lengths in a bell crank, it is appreciated thatthat system may be applied using cables and pulleys as well.

The hydraulic equivalent of FIG. 4 is shown in FIG. 5. In particular,FIG. 5 is particularly suited for use with suspension systems alreadyhaving hydraulic components. While jacking cylinders 580 and 582 areshown separately from and above inner and outer springs 522 and 524, itcan be appreciated that these components may be integrated into a singleunit or jacking cylinders may be placed between the spring andsupporting means if desired. In particular, inner and outer jackingcylinders 580 and 582, respectively, are interposed between chassispickups 528 and the upper ends 522b and 524b of inner and outer springmeans 522 and 524, respectively. A lateral jacking cylinder 584 ismounted at one end to body 514 at its other end to axle 518. Cylinder584 has a piston 584c therein which is connected to rod 586. First side584a is connected via line 587 to inner jacking cylinder 580 whilelateral jacking cylinder second side 584b is connected via line 588 toouter jacking cylinder 582. As can be seen in the phantom portion ofFIG. 5, the jacking effect which takes place in this embodiment is quitesimilar to the mechanical analogue of FIG. 4.

The embodiment shown in FIG. 6 is similar to that shown in FIG. 3 andutilizes as part of suspending means 620 a toggle spring 690 whichprovides a downward force on toggle link 691 which is in turn pivotablyattached to subframe 650. When entering the cornering mode, togglespring 690 provides a lateral force increasing the lateral movement ofbody 614 relative to wheel supporting means 616 and which also serves toincrease jacking. A conventional antisway bar 692 is mounted to body 614and has at either end thereof links 694. Antisways bar 692 serves toeliminate the destabilizing effect of toggle spring 690 that otherwisecould cause the body to fail to return to center after moving to theside. Any conventional spring that is not part of the antiswaysuspension would have this effect.

Turning to FIG. 7 this embodiment is highly suited (but not limited) tofront wheel drive cars where the cost and complexity of allowing lateraltranslational movement of the front wheels could be prohibitive. Inparticular a rear wheel 713 is mounted to jacking cylinder 784 whichtranslates the inertia of body 714 into lateral movement relative towheel supporting means 716. At the front body 714 is suspended fromjacking cylinders 780 and 782 and spring means 722 and 724 which areportions of antisway bar 721. Jacking cylinders 780, 782, and 784 alongwith hydraulic lines 787 comprise a system for jacking spring means 722and 724. In particular the first side 784a of lateral jacking cylinder784 is connected to the bottom side of 782b of jacking cylinder 782 andthe top side 780a of jacking cylinder 780. Correspondingly the secondside 784b of jacking cylinder 784 is connected to the top side 782a ofjacking cylinder 782 and the bottom side 780b of jacking cylinder 780.This allows lateral movement of the rear wheel to be converted into ajacket effect at the front axle of the vehicle. On a vehicle with morethan three wheels, rear spring means could be jacked as well, asdesired.

FIG. 8 discloses an embodiment which may be applied to yield asuspension having anti-dive and anti-squat characteristics. Inparticular, the principle of utilizing movement in the suspension is inthis case applied in a fore-aft direction. In FIG. 8, the wheel 812 ismounted on a wheel supporting means 816 which may be a MacPherson, strut816 which is in turn mounted to body structure 814. A spring means 840is pivotally mounted at its upper end to body structure 814 and itslower end to strut 816. In an anti-dive configuration shown in FIG. 8,spring means 840 angles upwardly and rearwardly. Fore-aft movement isfurther controlled by a drag strut 832 having a shock absorber 832mounted therewith. Thus, as the vehicle brakes, wheel 812 and wheelsupporting means 816 tend to move rearwardly thereby causing shockabsorber 832a to allow some rearward movement thereby jacking the bodystructure 814 upwardly as spring means 840 is rotated thereby decreasingor eliminating dive during braking. Of course, it may be appreciatedthat similar geometry may be utilized at the rear of the car to yieldanti-squat capabilities.

Of course it can be appreciated that the anti-pitch embodiment of FIG. 8may be applied in a manner similar to that of FIGS. 1 and 5. In such anapplication, front and rear axles would be tied together in a manneranalogous to the side-to-side tie of the anti-roll embodiment.

While the preferred embodiments of the present invention have beendescribed, it is understood that individual features such as springtype, linkages, wheel supporting and suspending means, etc., may becombined any variety of ways, and in some cases combined withconventional features, and that various changes, adaptations, andmodifications have been made therein without departing from the spiritof the invention and the scope of the appended claims.

What is claimed is:
 1. An anti-pitch suspension for suspending at leastone wheel from a vehicle body, said suspension comprising:wheelsupporting means, at least one said wheel being mounted to saidsupporting means; spring means associated with at least one said wheel;means suspending said body from said wheel supporting means, saidsuspending means comprising means for translating the fore-aft inertiaof said vehicle body during fore-aft acceleration into substantialfore-aft translational movement of said vehicle body relative to saidsupporting means; and means for converting said vehicle body fore-afttranslational movement into increased compression of at least one saidspring means independent of vertical movement of said wheel due to bumpsand other non fore-aft accelerative forces.
 2. The anti-pitch suspensionof claim 1, said spring means having a first end pivotably attached tosaid supporting means and a second end pivotably attached to saidvehicle body.
 3. The anti-pitch suspension of claim 2 wherein saidvehicle body comprises:at least first and second axles; a center betweensaid axles, said spring means angling from said first end towards saidcenter, said second end being closer to said center than said first end.4. The anti-pitch suspension of claim 3 further comprising means forinterconnecting said spring means on said first axle and said springmeans on said second axle.
 5. The anti-pitch suspension of claim 4wherein said interconnecting means increases compression of said springmeans on said first axle and decreases compression of said spring meanson said second axle.
 6. An anti-roll suspension for suspending at leastone wheel from a vehicle body, said suspension comprising:a wheelsupporting means, at least one of said wheels being mounted to saidsupporting means; a torsional bar mounted to said vehicle, said barhaving at least a first actuating arm; and means suspending said bodyfrom said wheel supporting means, said suspending means comprising meansfor translating the lateral inertia of said vehicle body duringcornering into lateral translational movement of said vehicle bodyrelative to said supporting means, said translating means comprising atleast a first link and said supporting means comprising at least a firstattachment point, said first actuating arm being above and toward thecenter of said vehicle relative to said attachment point, said linkconnecting said attachment point and said first actuating arm, said linkangling upwardly and inwardly from said point to said arm.
 7. Thesuspension of claim 6 wherein said torsion bar is a sway bar.